In the Marvel Universe, there are several types of threats that bring the heroes of the 616 universe together. From street level mob wars that tear apart New York City, to attacks from other dimensions and other magical realms and even cosmic threats that have destroyed the entire Multiverse, the threats are always constant and challenging the heroes in new ways.
One type of menace the superheroes face often in the comics is aliens. While many aliens are allies of the Marvel Heroes and often become Avengers and heroes themselves, let’s look at the ten most evil aliens who have appeared in the Marvel Universe.
10 Badoon
The first alien race is the Badoon. A race of beings who arrived in the cosmos well before the Kree and Skrull Empires became cosmic powerhouses. What made the alien race so distinct is that it is divided up between the male and female genders, resulting in a long gender war.
When the males won, they left the women on their homeworld to conquer other worlds, only returning to mate and continue the population. The men are violent and conquerors while the women are pacifists in nature. They have fought the Guardians of the Galaxy, New Mutants, and more in the Marvel Universe.
9 Poisons
A more recent and powerful alien threat to the multiverse emerged in the form of the Poisons. These crystalline beings from Earth-17952 were being hunted by larger beasts until they discovered the ability to assimilate and control the symbiotes and their hosts, increasing the Poisons' power and numbers to make them galactic threats.
After Venom was brought along with other Marvel heroes from the Multiverse who had been venomized to fight the Poisons, the Poisons’ second in command, Poison Thanos, was told of the Multiverse by Poison Doctor Doom, and set about conquering other realities with his Poison army.
8 Chitauri
This next alien race is now iconic thanks to the MCU, and that is the Chitauri. The aliens were the invading force that Loki used to attack New York City in Marvel’s The Avengers. Originally created for Ultimate Marvel's 1610 universe as a replacement for the Skrulls, these creatures attacked Ultimate Marvel Earth in WWII and again in the modern era.
Integrated into the 616 universe after their MCU debut, the Chitauri have been seen as an opposing force to Nova. They were also used by the Hydra-controlled Steve Rodgers during Secret Empire, who took a Chitauri egg to lure the armada to Earth and keep many heroes trapped outside Earth occupied.
7 Dire Wraiths
One powerful alien race that is not mentioned nearly enough is the Dire Wraiths. These shape-shifting aliens are a genetic Deviant race of the Skrulls, created by the all-powerful Celestials. What distinguishes these beings from the Andromeda galaxy however is that they are more in tune with dark magic than most alien beings.
Outcasts of the Skrulls due to their dark magic, the Dire Wraiths settled on a planet in the Dark Nebula and named it Wraithworld, connecting to the raw power of a black sun to practice their dark magic. They would battle the X-Men and other Marvel heroes for many years.
6 Outriders
The Outriders are a single-minded and powerful race of aliens in the Marvel Universe. These creatures serve Corvus Glaive and Thanos, completing missions for the latter until their dying breath. The most memorable moment for the Outriders came during the Infinity series.
In this series, Outriders were shown to be the ones who found planets for Thanos to conquer. The planets would offer a tribute to Thanos or they would end up razed. An Outrider flew to Earth and extracted memories for Thanos out of Black Bolt’s mind before the hero awoke and took one of the creature’s arms. However the creature escaped, and after relaying its message back to its superiors, the Outrider received a gift: The end of its life.
5 Skrulls
One alien race that has straddled the line between villains and ordinary citizens are the Skrulls. For years, they were seen as the shape-shifting villainous aliens who invaded Earth and nearly destroyed the planet. However, the history of the Skrulls is much more complex than that.
Created by the Celestials long ago, a war between the Eternals, Deviants, and Prime Skrulls broke out until the Deviant’s shape-shifting won the war. The last Eternal Skrull and the Deviant Skrull leaders fell in love and eventually became their gods. Later when they developed space travel, a delegation arrived on Hala, the Kree homeworld, where the barbaric Kree wiped them out and took their technology for their own purposes.
4 Phalanx
The next alien race that have served as a menace to the Marvel Universe for years are the Phalanx. A race of cybernetic aliens who were once thought to be organic creatures infected with the Technarchy’s techno-organic virus, Power of X #2 reframed the aliens as A.I. that operates purely on a galactic scale.
The Phalanx go from planet to planet, judging the various races on whether or not they are worthy of having their memories and personalities integrated into the Phalanx Hivemind. They often battle the X-Men, such as Emma Frost and even Wolverine.
3 Brood
One of the most vicious and brutal alien races to ever face the Marvel Universe has to be the Brood. The aliens are the universe’s first natural-born predators, who emerged onto a dark galaxy before Galactus emerged from his incubator at the beginning of time.
Much like Xenomorphs from Alien, the Brood have the ability to implant victims with an egg, which when hatched turns the host into a new member of the Brood. They are so powerful that they are able to infect heroes and even demons or those possessed by demons, much like Ghost Rider.
2 Beyonders
The second most powerful group of aliens to ever attack the heroes of the Marvel universe, even the Multiverse, is the Beyonders. Unlike the villain the Beyonder, these alien species are extra-dimensional beings with the power and ability to capture and take planets. They remained a secret for a long time, never able to leave their home dimension and avoiding even the eyes of the Watchers.
They are so powerful that in the Time Runs Out event leading up to Secret Wars, the Beyonders took the lives of the Celestials, the Living Tribunal, and other all-powerful cosmic entities. Doctor Doom, however, stole their collective power, becoming God Emperor Doom.
1 Kree
Of all the alien species to ever attack or bring change to the Marvel Universe, none are more devious or brutal than the Kree. While some heroes like Mar-Vell have been born of the Kree Empire, the empire as a whole is brutal.
Beginning their space-faring ways by destroying the Skrull envoy and taking their technology, they began a war with the Skrulls. They performed genetic experimentation and even sent villains like Ronan the Accuser to fight their battles, all working under the eye of the Supreme Intelligence, an all-powerful being that dominates Hala.